pleasure vs. happiness

I've been rereading Dorian Gray, and there's a lot I love about it that isn't written in this post yet- but one of the chief themes is the idea of pleasure as compared to happiness.
First of all, they're two different things. If Happiness is the opposite of suffering, then pleasure is as Milan Kundera writes (in Slowness)"the fundamental notion of hedonism... since pleasures often bring more unhappiness than happiness".
So what I can gather lately is to be happy doesn't mean necessarily needing to experience all the things in this world that might feel good or bring pleasure. I used to admire Dorian because he didn't have a conscience, (and wanted to take advantage of his youth, and experience all things) but eventually the constant hiding of it kills you, so I think it'd be better to live with one. and be happy.
I think he actually states at one point in the book, when a woman asks him if he's been happy, that he's gotten a lot of pleasure out of life, but can't say that he's been happy for most of it.